The present invention relates to the use of a chemical additive to improve the feed efficiency and to increase the rate of weight gain of ruminating animals which are fed a roughage diet.
The use of chemical additives to enhance the weight gain of animals is old. For example, monensin sodium, sold under the trade name RUMENSIN, has been used as a chemical additive for feeds for ruminating animals. Monensin is a complicated organic compound having the following name: 2-(5-ethyltetrahydro-5-(tetrahydro-3-methyl-5-(tetrahydro-6-hydroxy-6-(hyd roxymethyl)-3,5-dimethylpyran-2-yl)-2-furyl)-2-furyl)-9-hydroxy-beta-methox y-alpha,gamma,2,8-tetramethyl-1,6-dioxaspiro(4,5)decane-7-butyric acid.
The present invention is particularly concerned with the use of captan and related compounds as chemical additives in feeds for animals. Captan is sold under the trade name ORTHOCIDE fungicide, and it has the following technical name: cis-N-[(trichloromethyl)thio]-4-cyclohexene-1,2-dicarboximide. Attention in the past has been given to captan in animal feeds from the point of view that seed corn treated with the fungicide captan may be available in excess of seed requirements and, hence, it would be desirable to feed the excess treated seed to animals if there are no adverse effects. An article by Dowe et al entitled "The Effects of Corn Treated with Fungicides Upon the Performance of Fattening Steers", February 1957, states at page 94:
"The rumen microorganisms that are vital to the nutritional well-being of steers are known to be sensitive to many compounds. Since the active ingredients in ARASAN and ORTHOCIDE are fungicides, it was felt that they might affect the rumen microorganisms and in turn the performance of fattening steers. This experiment was conducted to obtain information on the toxicity of these materials and their effects on the feed consumption and gain of such animals."
In Dowe et al's experiments, steers were fed various levels of captan in a "concentrate" ration of 67% corn and 33% alfalfa.
The term "concentrate feeds" is used herein to refer to feeds containing 1/3 or more corn, wheat grain, sorghum grain, or the like relatively high-carbohydrate-content constituents. The term "roughage feeds" is used herein to refer to feeds containing 70% or more alfalfa, corn-silage, forage sorghum, clover hay, fescue hay, or other relatively highly cellulosic feed.
Dowe et al reported that the best average daily weight gains were observed by them at about 370 ppm captan (calculated as 100% technical captan by weight), second-best at 184 ppm, and smallest average daily weight gains at 736 ppm captan in the concentrate feed.
In a report to the American Seed Testing Association (ASTA) entitled "Tissue Residue Study for captan and Tetrahydrophthalamide in Crossbred Fed Technical captan" dated Dec. 6, 1972, the authors mainly discuss whether captan causes any ill effects in the cattle tissue. The report also contains a table on page 8, which is as follows (except that the Table number has been changed from II to I):
TABLE I ______________________________________ TEST MATERIAL: Technical captan Tissue Residue Study - Crossbred Steers Test Period Feed Efficiency Data Dietary Food Level Consumption Rate of Gain Feed Group (ppm) (lbs/steer/day) (lbs/steer/day) Efficiency ______________________________________ C None 15.97 0 0 T-I 100 13.93 1.25 0.090 T-II 600 14.83 -4.18 -0.306 T-III 1200 14.85 0.50 0.034 ______________________________________ *Total gain/feed consumed
The food consumption that was measured and presented in tabular form by the table was that of grain consumption (primarily corn grain), so that the above results were for a concentrate feed. However, the test cattle were also allowed to eat prairie clover at their pleasure. The test may not generally be regarded as valid for measurement of feed efficiency or weight gain rate because it was not intended therefor but instead was a tissue residue study.